Clip for fire detector wire

ABSTRACT

A clip assembly ( 111 ) having a clamp member ( 115 ) with opposing fingers ( 121  and  123 ) configured to form a channel, and an insert member ( 129 ) that holds the fire detector wire ( 128 ) is disclosed. The insert member ( 128 ) is made of, coated with, or treated with an anti-friction material. The insert member includes end flanges (133, 135) that retain the insert member between the opposing fingers. The fire detector wire is installed into the insert member, and the insert member is then snapped into the channel formed by the opposing fingers of the clamp member.

TECHNICAL FIELD

The present invention relates to mounting clips. In particular, thepresent invention relates to mounting clips for fire detector wires inaircraft.

DESCRIPTION OF THE PRIOR ART

Fire detector wires have been in used in aircraft for many years. Theyare installed in aircraft at selected locations to produce warningsignals when fires break out or when temperatures exceed predeterminedlimits. These fire detector wires typically consist of two non-insulatedelectrical conductors in a sealed tube filled with a dielectric materialor a gaseous material. If the temperature of the fire detector wireexceeds a predetermined temperature limit, the dielectric materialbreaks down, causing the non-insulated electrical conductors to shortcircuit. This short circuit is detected and a corresponding signal issent to the cockpit to alert the pilot that the temperature in thevicinity of the fire detector wire has exceeded the predetermined limit.Any damage to the sealed tube of the fire detector wire can result in aloss of the dielectric material or the gaseous material and failure ofthe fire detector wire.

These fire detector wires are typically mounted to the aircraftstructure with mounting clips. The purpose of the mounting clips is toprevent the fire detector wire from coming into direct contact with theaircraft structure. These mounting clips usually include a flat baseportion and an upraised clamp portion. The mounting clip is installedonto the aircraft by fastening the base portion to the aircraftstructure at a selected location. Then the fire detector wire is snappedinto the clamp portion.

One of these mounting clips is shown in FIGS. 1A and 1B in the drawings.A prior-art clip 11 includes a flat base portion 13 and an upraisedclamp portion 15. Base portion 13 includes a single mounting aperture 17through which a fastener (not shown) passes to secure clip 11 to astructure 19 of an aircraft. Clamp portion 15 includes a plurality ofopposing fingers 21, 23, and 25 that act as springs and form a channel27 for receiving a fire detector wire (not shown). Clip 11 typicallyincludes a surface lubricant to protect against fretting between baseportion 13 and structure 19.

Other prior-art fire detector mounting clips involve loop-type clampsand hinges. These clips require complicated moving parts that must befastened after the fire detector wire is installed. This can be a verylabor intensive task, as the clips are often Installed in hard to reachplaces. On some of these clips, the clamping portions may be lined withrubber or plastic sleeves. These loop-type clips are very expensive andtypically stand much higher than the finger-type clips.

All of these prior-art clips for fire detector wires have significantproblems. For those with only one mounting aperture, the clips tend torotate when subjected to vibration. This causes crimping and chafing ofthe fire detector wire. In addition, because there is not sufficientanti-friction protection between the opposing fingers and the firedetector wire, chafing of the fire detector wire can take place when theclip is subjected to vibration. For those with closed loops and hinges,they stand too high and involve too much time and labor to install.

Thus, many shortcomings remain in the area of mounting systems for firedetector wires in aircraft.

SUMMARY OF THE INVENTION

There is a need for a clip for a fire detector wire in an aircraft thatdoes not rotate when subjected to vibration, and that providessufficient means of preventing crimping and chafing of the fire detectorwire.

Therefore, it is an object of the present invention to provide a clipfor a fire detector wire in an aircraft that does not rotate whensubjected to vibration, and that provides sufficient means of preventingcrimping and chafing of the fire detector wire.

These objects are achieved by providing a clip assembly having a clampmember with opposing fingers configured to form a channel, and an insertmember that holds the fire detector wire. The insert member is made of,coated with, or treated with an anti-friction material. The insertmember includes end flanges that retain the insert member between theopposing fingers. The fire detector wire is installed into the insertmember, and the insert member is then snapped into the channel formed bythe opposing fingers of the clamp member.

The present invention provides significant benefits and advantages,including: (1) the clip does nor rotate relative to the aircraftstructure when subjected to vibration, thereby preventing crimping andchafing of the fire detector wire; (2) the anti-friction insert memberprevents chafing of the fire detector wire; (3) the end flanges of theinsert member retain the insert member in the proper position betweenthe opposing fingers of the clamp member; and (4) once the insert memberis installed into the clap member, no further fastening or adjustment isrequired.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 A is a top view of a prior-art clip for a fire detector clip.

FIG. 1 B is a front view of the prior-art clip of FIG. 1 A.

FIG. 2 is an assembled perspective view of the clip for fire detectorwire according to the present invention.

FIG. 3 is a top view of the clip member of the clip of FIG. 2.

FIG. 4 is a front view of the clip member of FIG. 3.

FIG. 5 is a right side view of the clip member of FIG. 3.

FIG. 6 is a front view of the insert member of the clip of FIG. 2.

FIG. 7 is an end view of the insert member of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is a clip assembly for retaining a fire detectorwire. The clip assembly of the present invention is shown In assembledform FIG. 2 and comprises a clip member 111 as shown In FIGS. 3-5, andan insert member 129 as shown in FIGS. 6 and 7. Although the presentInvention will be described with respect to an aircraft application, itshould be understood that the clip assembly of the present invention maybe used in any vehicle or structure in which it is desirable to installa fire detector wire.

Referring now to FIG. 2 and FIGS. 3-5 in the drawings, clip member 111is illustrated. Clip member 111 Includes a flat base portion 113 and anupraised clamp portion 115. Base portion 113 includes at least twomounting apertures 117 through which are passed conventional fasteners(not shown) for securing clip member 111 to an aircraft structure 119.The presence of at least two mounting apertures 117 prevents clip member11 from rotating relative to structure 119.

Base portion 113 transitions into a clamp portion 115 that includes aplurality of upraised finger members 121, 123, and 125. Finger members121, 123, and 125 extend up from base portion 113 at a selected angle Afrom structure 119. In the preferred embodiment, angle A is about 25°.Finger members 121, 123, and 125 extend up in a co-planar fashion for ashort distance, and then finger members 121 and 123 transition intodownward facing curves, while finger member 125 transitions into anopposing upward facing curve. These opposing curves form a channel 127that is configured to releasably receive insert member 129. Opposingfinger members 121, 123, and 125 act as springs to secure insert member129 in place. Although channel 127 does not have a completely circularcross section, channel 127 has a minimum clearance C. This configurationensures that a fire detector wire 128, which is secured within insertmember 129, does not come into direct contact with structure 119.

Clip member 111 is preferably manufactured from a metallic material withsufficient elastic properties to perform the desired spring functions.In the preferred embodiment, at least base portion 113 is coated with,or otherwise treated, with a lubricant to prevent fretting between baseportion 113 and structure 119.

Referring now to FIG. 2 and FIGS. 6 and 7 in the drawings, insert member129 is illustrated in a front view and an end view, respectively. Insertmember includes an elongated shaft portion 131 that terminates withflanges 133 and 135 on the opposing ends. Insert member 129 includes anaxial central channel 137 that extends along the entire length of insertmember 129. Although central channel 137 is shown having a circularcross-sectional geometry, it should be understood that the geometriccross-sectional shape of central channel may be other than circular toaccommodate the cross-sectional shape of fire detector wire 128. Alongitudinal slot 139 extends along the entire length of insert member129, and allows access to central channel 137. Fire detector wire 128 isinserted into slot 139 and pressed into central channel 137. In thepreferred embodiment, the width T of slot 139 is smaller than thediameter of central channel 137. This configuration facilitates thesecuring of fire detector wire 128 within central channel 137.

Shaft portion has a length L between flanges 133 and 135 that isdimensioned to correspond to a width W between the outside edges offinger members 121 and 123. This ensures that flanges 133 and 135 remainon the outside of finger members 121 and 123, and that insert member 129does not move axially while held in place between finger members 121,123, and 125. In addition, shaft portion has an outside diameter Dbetween flanges 133 and 135 that Is dimensioned to correspond toclearance C between the curves formed by finger members 121, 123, and125, such that a small compressive load is exerted upon insert member129 by finger members 121, 123, and 125.

In the preferred embodiment, insert member 129 is made ofpolytetrafluoroethylene. However, it should be understood that inalternate embodiments other suitable anti-friction materials may beused, or insert member 129 may be manufactured from other materials,covered with, coated with, or otherwise treated withpolytetrafluoroethylene or any other suitable anti-friction material.

In operation, clip member 111 is secured to structure 119 by passingconventional fasteners through mounting apertures 117. Then, firedetector wire 128 is inserted through slot 139 into central channel 137of insert member 129. Insert member 129 and fire detector wire 128 arethen snapped into channel 127 of clip member 111. No other clamping,fastening, hinging, or adjusting is required.

The multiple fasteners prevent clip member 111 from rotating relative tostructure 119 due to vibration of the aircraft. This prevents crimpingand chafing of fire detector wire 128. Insert member 129 is held inplace by flanges 133 and 135. This further prevents chafing of firedetector wire 128.

The present invention provides significant benefits and advantages,including: (1) the clip does nor rotate relative to the aircraftstructure when subjected to vibration, thereby preventing crimping andchafing of the fire detector wire; (2) the anti-friction insert memberprevents chafing of the fire detector wire; and (3) the end flanges ofthe insert member retain the insert member in the proper positionbetween the opposing fingers of the clamp member.

It is apparent that an invention with significant advantages has beendescribed and illustrated. Although the present invention is shown in alimited number of forms, it is not limited to just these forms, but isamenable to various changes and modifications without departing from thespirit thereof.

1. A clip for mounting a fire detector wire to a structure comprising: aclip member comprising: a base portion adapted for mounting to thestructure; at least two mounting apertures passing through the baseportion; and a clamp portion upraised from the base portion havingopposing spring action finger members; an anti-friction insert memberadapted to carry the fire detector wire comprising: an elongated shaftportion; an axial central channel for receiving the fire detector wire;a longitudinal slot for allowing access to the central channel; and aflange on each end of the elongated shaft; wherein the insert member isconfigured to be releasably clamped between the finger members, theflanges preventing axial movement of the insert member relative to thefinger members.
 2. The clip according to claim 1, wherein the springaction finger members include opposing curves that define a channelconfigured to clampingly receive the insert member.
 3. The clipaccording to claim 1, wherein the insert member is made ofpolytetrafluoroethylene.
 4. The clip according to claim 1, furthercomprising: a lubricant disposed between the base portion and thestructure.